Draw arcs and rings
Use Arc for an open circular segment and Ring for a circular band.
Choose Arc or Ring from Add Objects. These produce different geometry: an arc is an open curved path; a ring has an outer and inner radius. A selects Arc in the 2D drawing.
Choose an Arc construction mode
The Construction Mode choices are 3-Point, Center + Angles and Start + End + Radius. The guide fields change with the mode. Use 3-Point to define a start, a point along the bend and an end.
Enter an arc precisely
In Center + Angles, enter Center, Radius, Start Angle and End Angle. In Start + End + Radius, enter the endpoints and radius. Arc Length is a readout. In 3-Point mode, Radius is also calculated from the three points.
Draw a ring
Choose Ring, place its Center and size its Outer Radius using the preview. Set Inner Radius for the opening. Check that the inner radius fits inside the outer radius; a ring is not made by leaving two unrelated circles overlapped.
Finish or cancel
Use the valid guide Apply action for entered values or complete the tool’s pointer sequence. Esc cancels unfinished placement. Undo reverses a completed object; select it to edit the resulting supported properties.